The present invention relates to a method for generating a computer program, and more particularly to a method for graphically representing a program to generate a programming language therefrom.
Many approaches to improve the productivity of program in a computer system have been attempted. Of those, an attempt to graphically represent a programming language to reduce a load of coding work by keyboard input (visual programming method) is an effective method. Many approaches have been proposed to graphically represent the programming language. Of those, an approach to define a combination of data and a process for processing it as a node, represent processed data by a port attached to the node and represent delivery of data by a line between ports has been studied widely because of its high representation ability and products therefor have been marketed.
Of those, Prograph marketed by Visual Programming Inc. described in "Using a Pictorial Representation to Combine Dataflow and Object-Orientation in a Language Independent programming Mechanism" (Proceedings International Computer Science Conference, p. 697-704, 1988) displays a process as a node. Data which is subject of process and a port representing argument data are provided at top and bottom of the node. The upper port represents input data and lower port represent data modified by the process. This graphic representation is suitable for a data flow type computation model in which data is sequentially modified in the process. Thus, prograph is provided with a library and a dedicated language to allow description of a general purpose program in a data flow form.
The graphically represented program based on the data flow type computation model is suitable for the description of control of a measuring instrument but it has the following problems. Namely, an infinite repetition such as that an output from one process is used as an input to another process and an output of the second process is used as an input to a subsequent process and so on must be inhibited. Further, in changing an execution order of the processes, the data reliance must be checked. Those problems mean that an edit work to modify the content of the program is difficult.
In a broad sense, the present invention intends to visually generate a program by using a graphic representation. However, the graphically represented program according to the present invention is not based on the data flow type computation model but based on procedural type computation model. This program may be described in most programming languages and is most widely used. Many computer hardware are most suited to the process of this computation model.